MOGRE 1.8.1 + WPF (C#) - Back Buffer is not valid when user changes resolution or computer goes to sleep

Question

I'm working with MOGRE 1.8.1 to embed 3D models within a WPF application. I've run into an issue where the application crashes when the user changes resolution or their computer goes to sleep. I believe this is because the render system is trying to draw to a surface that it doesn't have access to anymore.

I'm not exactly sure what to do; I've tried using the dispose method to kill MOGRE and reboot it later (by catching the windows event), but have run into a memory leak. The pause render method included within the MOGRE library does not seem to work either. Does anyone have any ideas on how to circumvent this issue?

Notes

• You can find the example I'm running here. Main difference is that I'm using the 1.8.1 .dlls instead -> http://www.codeproject.com/Articles/29190/Blend-the-OGRE-Graphics-Engine-into-your-WPF-proje , but the error is present in both.
• OgreImage.cs is where the issues are happening.

Thank you for your help.

Answer 1

This error happen when the device is lost, so you have to add your control in the function RenderFrame()

//WallPaper, CTRL + ALT + DEL, etc
        if (this.isDeviceLost)
        {
            //Recreate the texture render
            ReInitRenderTarget();

            //Restore device lost
            _renderWindow._beginUpdate();
            _renderWindow._endUpdate();

            _reloadRenderTargetTime = -1;
            this.isDeviceLost = false;
        }

And this is my ReInitRenderTarget() function

protected void ReInitRenderTarget()
    {
        DetachRenderTarget(true, false);
        DisposeRenderTarget();

        _texture = TextureManager.Singleton.CreateManual(
            "OgreImageSource RenderTarget",
            ResourceGroupManager.DEFAULT_RESOURCE_GROUP_NAME,
            TextureType.TEX_TYPE_2D,
            (uint)ViewportSize.Width, (uint)ViewportSize.Height,
            0, Mogre.PixelFormat.PF_R8G8B8A8,
            (int)TextureUsage.TU_RENDERTARGET);//, null, false, 8);

        _renTarget = _texture.GetBuffer().GetRenderTarget();

        _reloadRenderTargetTime = 0;

        int viewportCount = ViewportDefinitions.Length;
        viewports = new Viewport[viewportCount];

        for (int i = 0; i < viewportCount; i++)
        {
            Viewport viewport;
            ViewportDefinition vd = ViewportDefinitions[i];
            viewport = _renTarget.AddViewport(vd.Camera, zIndexCounter++, vd.Left, vd.Top, vd.Width, vd.Height);
            viewport.BackgroundColour = vd.BackgroundColour;
            viewports[i] = viewport;
        }

        var ev = ViewportsChanged;
        if (ev != null) ev();

        viewportDefinitionsChanged = false;
    }